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Elevated levels of PFAS found in water in Miami, New York, Philadelphia, other major cities



Jan. 22 (UPI) — A new study of tap water samples across the United States has revealed PFAS compounds, human-made chemicals linked with a variety of health problems, to be more prevalent than earlier surveys.

The new study, organized by the Environmental Working Group, involved the testing of tap water samples from 44 locations in 31 states.

“We found PFAS in all but one sample, which is pretty incredible,” Sydney Evans, science analyst with EWG, told UPI.

Tests revealed elevated levels of PFAS in dozens of American cities, including Miami, New York, Philadelphia and Washington, D.C.

Per- and polyfluoroalkyl substances, or PFAS, are a class of synthetic compounds used in a variety of industrial processes and found in dozens of household items. The newest research suggests these chemicals are also accumulating in drinking water sources in cities across the United States.

Previous studies have linked PFAS with a variety of health problems, including cancer and high cholesterol. Research suggests PFAS compounds can disrupt the development of a fetus and depress the efficacy of vaccines.

“These compounds don’t break down,” Evans said. “Once they’re there, they’re there forever. That’s why we call them ‘forever chemicals.’ And they’re toxic at very low levels over long periods of time.”

Previous efforts to test for PFAS in water samples were limited in their scope. Earlier efforts also weren’t able to identify PFAS compounds at very low levels. The latest tests were able to identify PFAS compounds at concentrations as low as 1 part per trillion, the equivalent of a drop or two of water in a body the size of three Olympic swimming pools.

Under pressure from the EPA, the two most infamous PFAS compounds, PFOA and PFOS, were phased out of production by major chemical companies like Dupont, but research suggests many other PFAS compounds — including compounds designed to be safe replacements for PFOA and PFOS — are similarly toxic.

“The more we look at the newer ones, we’re seeing the same kinds of toxicity,” Evans said.

There are a variety of factors, including their longevity, that make PFAS especially problematic.

“Most pollutants stick to sediment or dissolve in oils, but because PFAS are water soluble, they spread out and travel great distances,” Rick Rediske, professor at the Annis Water Resources Institute in Michigan, told UPI.

“The most significant factor, from a toxicology standpoint, is that certain ones stick to proteins in our blood,” Rediske said. “DDT and pesticides go in to our fat. Lead goes into our bones. Mercury goes into muscle. Because PFAS are carried around in our blood and aren’t discarded, they naturally concentrate over time. And they attach to the proteins that carry antibodies, cholesterol and hormones, that’s why you get so many different health effects caused by these compounds.”

The latest EWG study tested for 30 different PFAS compounds, but there are currently 600 PFAS compounds currently being used by various industries. Most of these aren’t well studied, so their potential toxicities aren’t understood.

Part of the problem is that researchers working to study the safety of these compounds and their prevalence in the environment can’t keep up with their production by industrial sources, who are not required to report the development of new PFAS compounds and are reluctant to share trade secrets.

In Europe, PFAS compounds are banned — not so in the U.S.

“There are no federal limitations on their use, on their discharge or on their presence in drinking water,” Evans said.

Evans, Rediske and other concerned scientists want to see the chemicals regulated as a class.

“If we can classify these as hazardous substances and mandate that their use and discharge are reported, then we will at least have a starting point of knowing what to test for,” Evans said.

While PFAS compounds are found in dozens of products, Rediske said the prevalence of the most toxic of the known PFAS compounds in drinking water are there as a result of the use of flame-retardant foams — particularly those used to put out aviation fires.

Previous testing has found extremely high levels of PFAS in water samples collected near U.S. Navy and Air Force bases.

“People tend not to care about cleaning up after there is an aviation accident,” Rediske said. “They’re just trying to put out the fire and save people’s lives.”

Some municipalities are currently working to remove PFAS from their local water systems using granulated activated charcoal, but such filtration systems are currently mandated — and they’re not cheap or easily scalable.

“It’s very effective, but it doesn’t work on some of the smaller compounds,” Rediske said. “There still are PFAS compounds that are in the water that are smaller and thought to be less toxic but we really don’t know.”

Evans said in addition to pushing for the EPA to regulate PFAS and regulate the compounds as an entire class, she and her colleagues will continue to advocate for more comprehensive testing. While the latest survey was the most comprehensive to date, she said the technologies used to test for PFAS continue to improve.

“The laboratory technologies are expanding, and the testing needs to keep up with that,” Evans said.

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Clouds make newer climate models more realistic, but also less certain



June 24 (UPI) — Efforts to improve the precision with which climate models simulate cloud processes have yielded more realistic models. New research suggests these efforts have also introduced greater uncertainty, according to a study published Wednesday in the journal Science Advances.

When the latest generation of climate models started producing results last year, researchers noticed that several models were predicting higher amounts of warming than previous models. The results of the new models inspired news headlines that suggested global warming might be worse than previously thought.

As researchers with the Coupled Model Intercomparison Project, CMIP6, soon found out, a few of the latest generation of models predicted smaller levels of warming than previous models. To identify the cause of this uncertainty, CMIP6 researchers decided some historical context was needed.

One way to measure and compare the predictions of different climate models is by calculating the equilibrium climate sensitivity, or ECS.

“It’s kind of an abstract measure, but it’s one these metrics that has been around for a long time,” Gerald Meehl, a senior scientist at the National Center for Atmospheric Research, told UPI.

Essentially, scientists double the CO2 in a model and let the simulation run its course until the climate stabilizes. Each model — and each new generation of models — produces a narrow range of warming, between 1.5 to 4.5 degrees Celsius, or 2.7 to 8.1 degrees Fahrenheit.

“This kind of range has been out there for some time, and with each successive generation of models has produced about the same range in terms of degrees,” Meehl said. “With the latest generation of models, the average warming has stayed roughly the same, but the range has gotten bigger than ever — at both the low and the high end.”

When Meehl and his colleagues asked members of the groups responsible for the 39 new CMIP6 models why they thought the ECS value got bigger, most of them pointed to clouds.

To improve the accuracy of the latest generation of climate models, scientists have worked hard to simulate small-scale cloud processes. But these efforts have introduced a variety of new interactions between clouds and tiny particles called aerosols — interactions that can produce contradictory results.

“For example, if you have polluted air, particularly sulfur dioxide, that can influence clouds. Sulfur dioxide is emitted from cars and factories, and it goes into the air and forms sulfate aerosols,” Meehl said. “When you see the sky and it looks orange and hazy, chances are that a lot of that is caused by an abundance of sulfate aerosols.”

According to Meehl, these aerosols operate as cloud condensation nuclei. When these aerosols seed clouds, they seed clouds with a lot more tiny droplets.

“That increased number of small droplets makes the cloud brighter, and it’s going to reflect more sunlight and have a cooling effect,” Meehl said.

But this phenomena, now rendered more precisely in climate models, can also yield the opposite effect.

“On the other hand, you’ve formed all these droplets in the sky, but the aerosols absorb some sunlight, warm the air, and evaporate some of the droplets and that reduces the amount of clouds,” Meehl said. “That allows a little more sun into the system, and now you have a warming effect.”

Cloud-aerosol interactions are just one example of new simulated intricacies that offer both greater realism and greater uncertainty. According to Meehl, there are a variety of interacting processes involving a variety of different cloud types at different altitudes.

“With more interacting processes, your level of uncertainty can go up,” he said.

But ECS isn’t the only way to test and compare climate models. Most climate modelers prefer to use transient climate response, or TCR.

“You increase CO2 at 1 percent per year, compounded, until the time you double the amount of carbon dioxide, which is usually about 70 years,” Meehl said.

TCR works on a smaller timescale and works more like actual climate change. When scientists calculated the TCR range for the newest generation of climate models, they got the same average warming value but a smaller range.

Meehl and his colleagues shared the ECS and TCR values produced by the latest CMIP6 models in the new paper.

In addition to putting the latest generation of climate models into historical context, Meehl hopes the new study will inspire cloud modeling improvements.

“We’re doing a better job of simulating the clouds themselves, but now we have these different feedbacks that give you more uncertainty,” he said.

Now that researchers have highlighted this uncertainty, Meehl hopes climate research institutions and the climate modeling community will work to address the issue by directing more funds to relevant observational and analysis programs.

“You can’t simulate what you don’t understand,” Meehl said.

And to understand how exactly clouds will effect climate and vice versa, in the future, scientists need more robust observational programs and better satellite measurements.

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SpaceX launch Friday would boost Starlink network to nearly 600



Astronauts return to space from U.S. soil

NASA astronauts Doug Hurley (L) and Bob Behnken, who flew the Crew Dragon spacecraft to the International Space Station, brief mission controllers about their experience in the new vehicle on June 1. Photo courtesy of NASA

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Antarctic sea ice loss is good news for the continent’s penguins



June 25 (UPI) — While climate scientists worry about the loss of sea ice in Antarctica, penguins are flapping their flippers in applause. According to a new study, published this week in the journal Science Advances, many penguins prefer the Southern Ocean unfrozen — the less sea ice, the better.

Researchers had previously illuminated a link between sea ice extent in Antarctica and breeding success among Adelie penguin colonies, but a correlation doesn’t prove causation, and so scientists decided to investigate further.

To find out what might explain the positive impact of reduced sea ice coverage on breeding success, scientists strapped a trio of instruments to several dozen penguins. The combination of GPS trackers, accelerometers and video cameras helped scientists track how the movements and behaviors changed over the course of several years, as sea ice extents waxed and waned.

“What is new in this study is that we used a variety of electronic tags to record penguin foraging behavior in the greatest detail yet, and found mechanistic link among sea ice, foraging behavior, and breeding success,” lead researcher Yuuki Watanabe, scientist at the National Institute of Polar Research, told UPI in an email.

The novel data revealed the ways in which ice coverage in Antarctica affects the way penguins move across their environs and access food resources.

“In the ice-covered seasons, penguins traveled slowly by walking and needed to find cracks in the ice, where they dived repeatedly,” Watanabe said. “They were able to dive only through cracks, which also means that the competition among penguins was severe.”

The data also showed that, not surprisingly, penguins move much more efficiently in the water than on ice. Adelie penguins travel four times faster by swimming than by walking.

When sea extent was minimal, data showed the penguins were able to travel more easily, swimming and diving wherever they pleased.

“They came back to the nest quickly, which means that chicks waiting at the nest had food more often,” Watanabe said. “Overall, foraging conditions improved by the loss of sea ice, which directly linked to improved breeding success. Put very simply, penguins are happier with less sea ice because they swim.”

Less sea ice also allows more sunlight to enter the ocean, fueling larger krill blooms. Krill serve as the main source of food for Adelie penguins.

The latest findings don’t hold for all of Antarctica, and in future studies, researchers hope to explore the effects of sea ice extent on different penguin species living in different parts of the continent.

“The relationship between sea ice and penguin reproductive success is apparently different in maritime Antarctica (e.g. Antarctic Peninsula) where sea ice is normally sparse,” Watanabe said. “There, penguins look happier with more sea ice, but mechanics are unclear. I would like to conduct research in that region to understand the general patterns over the whole Antarctica.”

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